[PATCH 1/1] nvme/host: Rescan namespace if ns_id is changed

[wenxiong at linux.ibm.com]

From: Wen Xiong <wenxiong at linux.ibm.com>

Hi all,

Namespace is not visible if we detach/delete/create/attach a namespace
on a new nvme device because of nguid is changed.

Like Keith's suggestion, we can do the 2nd ns-attach to get new
namespace available. Test team likes to fix it in the driver.

The following patch has been tested by test team and works fine.

Appreciate your suggestion for difference approach!

Thanks,
Wendy

Signed-off-by: Wen Xiong <wenxiong at linux.ibm.com>
Tested-by: tjo at us.ibm.com

---
 drivers/nvme/host/core.c | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 88b54cdcbd68..a608a63d3108 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -3721,13 +3721,15 @@ static void nvme_ns_remove_by_nsid(struct nvme_ctrl *ctrl, u32 nsid)
 	}
 }
 
-static void nvme_validate_ns(struct nvme_ns *ns, struct nvme_ns_info *info)
+static bool nvme_validate_ns(struct nvme_ns *ns, struct nvme_ns_info *info)
 {
 	int ret = NVME_SC_INVALID_NS | NVME_SC_DNR;
+	bool ns_id_changed = false;
 
 	if (!nvme_ns_ids_equal(&ns->head->ids, &info->ids)) {
 		dev_err(ns->ctrl->device,
 			"identifiers changed for nsid %d\n", ns->head->ns_id);
+		ns_id_changed = true;
 		goto out;
 	}
 
@@ -3741,21 +3743,24 @@ static void nvme_validate_ns(struct nvme_ns *ns, struct nvme_ns_info *info)
 	 */
 	if (ret > 0 && (ret & NVME_SC_DNR))
 		nvme_ns_remove(ns);
+
+	return ns_id_changed;
 }
 
-static void nvme_scan_ns(struct nvme_ctrl *ctrl, unsigned nsid)
+static bool nvme_scan_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 {
 	struct nvme_ns_info info = { .nsid = nsid };
 	struct nvme_ns *ns;
 	int ret;
+	bool ns_rescan = false;
 
 	if (nvme_identify_ns_descs(ctrl, &info))
-		return;
+		return false;
 
 	if (info.ids.csi != NVME_CSI_NVM && !nvme_multi_css(ctrl)) {
 		dev_warn(ctrl->device,
 			"command set not reported for nsid: %d\n", nsid);
-		return;
+		return false;
 	}
 
 	/*
@@ -3777,15 +3782,17 @@ static void nvme_scan_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 	 * becomes ready and restart the scan.
 	 */
 	if (ret || !info.is_ready)
-		return;
+		return false;
 
 	ns = nvme_find_get_ns(ctrl, nsid);
 	if (ns) {
-		nvme_validate_ns(ns, &info);
+		ns_rescan = nvme_validate_ns(ns, &info);
 		nvme_put_ns(ns);
 	} else {
 		nvme_alloc_ns(ctrl, &info);
 	}
+
+	return ns_rescan;
 }
 
 static void nvme_remove_invalid_namespaces(struct nvme_ctrl *ctrl,
@@ -3837,7 +3844,9 @@ static int nvme_scan_ns_list(struct nvme_ctrl *ctrl)
 
 			if (!nsid)	/* end of the list? */
 				goto out;
-			nvme_scan_ns(ctrl, nsid);
+			if (nvme_scan_ns(ctrl, nsid))
+				nvme_scan_ns(ctrl, nsid);
+
 			while (++prev < nsid)
 				nvme_ns_remove_by_nsid(ctrl, prev);
 		}
-- 
2.39.3